Research On Wavelet Denoising Of Aerial Geomagnetism In Geomagnetic Matching Navigation

Geomagnetic matching navigation has been widely used in resource exploration,seismic research,and military applications,especially with unique advantages such as autonomy,allweather,passive and radiation free,and strong concealment,which has attracted more and more attention in the field of navigation.In the process of geomagnetic matching navigation,the geomagnetic signal is inevitably affected by the interference of magnetic sensors,and their equipment,resulting in an impact on the accuracy of aerial geomagnetic signals.As the data basis for geomagnetic matching navigation,the accuracy of geomagnetic signals directly affects the positioning accuracy.Therefore,denoising aerial geomagnetic signals to obtain highprecision measurement data will be beneficial for conducting research on high-precision geomagnetic matching navigation.This paper aims to conduct denoising research on geomagnetic signals in geomagnetic matching navigation,and use wavelet threshold denoising method to conduct experimental analysis on aerial geomagnetic signals and daily station geomagnetic signals.The main content of the paper is as follows:(1)Overcoming the shortcomings of traditional modeling methods for magnetic measurement errors that do not have universality,the geomagnetic signal is treated as a onedimensional physical signal,and wavelet denoising is used to remove noise from the geomagnetic signal.By comparing and analyzing the advantages and disadvantages of different wavelet denoising methods in signal denoising,the wavelet threshold denoising method was selected for analysis and research,and the selection of the optimal parameter combination for the wavelet threshold denoising method was completed.(2)Through simulation experiments,it was found that the wavelet threshold method is more suitable for denoising geomagnetic signals.A comparative simulation experiment was conducted on the wavelet threshold denoising method and the EMD based wavelet threshold denoising method for geomagnetic signals with 0.5n T and 1n T noise added.The results showed that the wavelet threshold denoising method has better denoising effect compared to the EMD based wavelet threshold denoising method.(3)The wavelet threshold denoising of geomagnetic signal based on IGRF13 model is studied.The wavelet threshold denoising was carried out on IGRF13 model terrestrial magnetic signals with 0.1n T,0.5n T,1n T and 2n T noises.The results showed that the denoising amplitude was between 60% and 85% when the noise with a standard deviation of 0.1n T was added,and the other denoising amplitude was between 80% and 92%.The wavelet threshold denoising method can suppress the noise of IGRF13 model geomagnetic signal.(4)The practical application of wavelet threshold denoising method in aerial geomagnetic signals was studied,and based on MAD algorithm,geomagnetic matching navigation experiments were conducted using the aerial geomagnetic signals before and after wavelet threshold denoising.Through experiments,it was found that the denoised aerial geomagnetic signal significantly improved the accuracy of geomagnetic matching positioning,verifying the effectiveness and feasibility of this method for noise removal in aerial geomagnetic signals.